There's not much in the way of an unifying motif for my criticisms of this section, so rather than shoe-horn in a thematic thesis as a preamble, I'm simply going to use my refusal to shoe-horn in a thematic thesis as a preamble...as a preamble.
Diving right in.
I am Jesus Christ, the Son of God, who was crucified for the sins of the world, even as many as will believe on my name, that they may become the sons of God, even one in me as I am one in the Father, as the Father is one in me, that we may be one.
Now, this isn't in the Book of Mormon, obviously, but it was a revelation given in the same year the Book of Mormon was published. There is no reason for this revelation to continue past the phrase "even one in me" if 1830 Mormonism were not influenced by Trinitarianism. You don't need to compare the amorphous, ill-defined unity of your followers to the amorphous, ill-defined unity between you and God the Father if you and God the Father are two completely separate beings whose coalignment can be so handily crystallized within the phrase "one in purpose."
We can debate whether the Book of Mormon is Trinitarian all we want, but when we broaden the playing field to include information from church history or other scripture, it sure does seem like the whole picture of early Mormonism leaned Trinitarian, which makes arguing about the Book of Mormon's Trinitarianism feel kind of moot.
And whoso shall ask it in my name in faith, they shall cast out devils; they shall heal the sick; they shall cause the blind to receive their sight, and the deaf to hear, and the dumb to speak, and the lame to walk.
And I have sent forth the fulness of my gospel by the hand of my servant Joseph; and in weakness have I blessed him;
Or maybe this is God's admission that he picked the wrong person to restore his church. After all, he doesn't say he blessed Joseph with weakness or weaknesses—he says he blessed Joseph in weakness. Maybe God's repudiation of Joseph Smith has been hiding out in scripture all along. It was a moment of weakness when God chose to bestow the mantle of restoration upon such a crappy guy. If only God could go back in time, he'd do everything differently on the second go.
This is certainly not proof of anything and it's not really even evidence of anything, but I do find it disappointing that, time and time again, this all-knowing perfected being is so careless with his wording.